Bacterial sensing and killing based on fluorescent vesicles formed by cationic Gemini surfactants and AIEgen probe

Abstract

In this work, a novel type of vesicles (VT/G) composed of Gemini cationic surfactant (G12-8-12) and TPE-2OH, an AIEgen fluorescence probe, were prepared by methanol evaporation method. Herein, G12-8-12 has good bacteriostatic function. TPE-2OH with aggregation-induced emission feature resided in the interlayer of VT/G. The average size of VT/G was about 1.2–1.4 μm measured by dynamic light scattering. Zeta potential studies indicated that VT/G could bind to bacteria like S. aureus and E. coli under electrostatic interaction, increasing the size of the complex of VT/G and bacteria to 4.5–6 μm. Because VT/G interlayer was compressed by external bacteria, the aggregation degree of TPE-2OH was increased, and the fluorescence intensity was increased by 3 times compared with VT/G alone. The linear increase in fluorescence intensity with the increase of bacteria content implied that it is possible to sense bacteria. After the bacteria were co-incubated with VT/G, almost no bacteria growth was observed with the light irradiation for 30 min, indicating that VT/G showed good bactericidal effect. This can be ascribed to the synergistic effect of the inherent bactericidal property of G12-8-12 and the oxygen-active substances generated from TPE-2OH. This new strategy integrating bacteria detection and killing showed good potential application.